The present application relates to an apparatus and method for removing water and other contaminants from fuel, and particularly to the use of a fiber optic cable and lens for viewing the presence of such water and contaminants.
Operation and maintenance have quickly become the new buzzwords in regulatory circles. Ask any inspector about underground storage tank compliance issues and the inspector will quickly cite leak detection, cathodic protection testing, piping, sumps and under-dispenser boxes as primary concerns. Water has this nasty habit of getting into places where it does not belong. This includes sumps, dispenser boxes, basements and even tanks. Water can enter tanks by way of the infrastructure, which includes pipelines, barges or trucks. But it can also enter an underground storage tank (UST) or above ground storage tank (AST) by condensation, fill boxes or tank sumps. Of course, a tank at a retail service station is the last place an owner-operator wants to find water. That water needs to be removed before it gets sucked into a motor vehicle's fuel tank, which can lead to irate motorists.
A number of organizations have developed recommended practices and standards to monitor water in tanks and provide for its removal. Before the days of automatic electronic liquid sensing and inventory devices, some operators daily used a special paste on a gauge stick to determine if water had entered the tank. American Petroleum Institute included procedures within their recommended practices with the goal to minimize the water content and maximize fuel quality. See API 1621, “Bulk Liquid Stock Control at RetailStations,” and API 2610, “Design, Construction, Operation, Maintenance, and Inspection of Terminal & Tank Facilities.” Steel Tank Institute recommends that water be removed from steel storage tanks on a regular basis within their tank installation and maintenance practices. Petroleum Equipment Institute's RP 100-2000, “Recommended Practices for Installation of Underground Liquid Storage Systems,” states, “Install tanks to facilitate water removal.”
For example, a tank can be sloped so that water collects at one end for easier removal. By removing the water, the life of the fuel filter and other dispensing-system components will be extended. More importantly, the gas-buying customer is assured of a quality fuel product. The question of how to address water in UST and AST systems has taken on added urgency during the last two decades as America's quest for cleaner air has led to new fuel blends featuring oxygenates. California is the largest state to ban the oxygenate MTBE. Major oil companies in California have already begun using ethanol and taken the necessary steps with their UST systems to ensure a smooth transition. With the replacement of MTBE by ethanol throughout America likely to take place during the next few years, the need to keep water out of tanks is an even more important task than ever before, as ethanol blends are very sensitive to water. (See www.steeltank.com for more on ethanol-blended fuels.) The operation and maintenance issues reach critical mass when ethanol combines with water and microscopic matter. Various microorganisms are carried in air and water.
Tanks with poor housekeeping are likely to see a buildup of sludge in conjunction with the water. The sludge serves as a breeding ground as the microorganisms multiply and form a potentially hazardous microbial colony, regardless of the type of tank material storing the fuel. Filters can be clogged frequently, product flow to the vehicle slows down, and the quality of fuel diminishes when such microbes begin to feed and grow in the water layer trapped at the tank bottom. In the case of steel, the microbes, or bugs, can create a corrosive environment. In plastic tanks where a high alcohol content has led to phase separation at the tank bottom, the plastic is subject to softening and can experience a reduction in its strength properties.
There is a need for an improved apparatus and method to remove water and other contaminants from fuel in fuel storage tanks.